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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Aquatic sciences 52 (1990), S. 299-314 
    ISSN: 1420-9055
    Keywords: Methods ; laboratory flume ; flush spills ; stormwater runoff pollution ; interstitial space ; Gammarus pulex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Urban stormwater runoff discharged through sewer systems into streams causes flush spills of water and pollutants in the receiving water. To make the right decisions in future plannings of the very costly rehabilitation of sewer systems, a solid ecological data base on the critical parameters of sewer overflows is badly needed. Therefore, we designed a laboratory flume which was operated in circular flow mode (to ensure adaptation of the test organisms) and in flow-through mode during the simulation of sewer overflows (to allow a proper evaluation of population loss by drift). Examples on the behaviour during the adaptation phase and the population loss during the exposure to flush spills of water and/or a mixture of sewage and clean water of a benthic invertebrate (Gammarus pulex) demonstrate the potential of the flume to identify critical parameters of sewer overflows at “quasireal-world-conditions”. We found clear evidence for synergetic effects since the exposure to high flow and sewage caused higher population loss ofGammarus than the sum of population loss at exposure to only high flow or only sewage. Population loss considerably depended on the availability of refugial space: if the interstices of the gravel in the flume were silted, this loss was higher than at open interstices. Only ten minutes of movement of the material forming the flume bottom reduced the population ofGammarus to about 60 or 50% of its initial size. Hence, our data strongly suggest that the characteristics of the receiving stream (refugial space, bed stability) play an important role for the potential ecological impact of a sewer overflow. Changes of stream morphology and/or creation of refugial space plus an appropriate technical solution for overflow treatment may be less costly and more effective than a large-scale technical project. Thus, the stream itself should be a major element in future management decisions.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 31 (1994), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 〈list xml:id="l1" style="custom"〉1Based on information obtained from analysis of thirteen taxonomic groups of plants and animals occurring in the alluvial floodplain habitats of the Upper Rhône River, France, we synthesize results obtained on: (i) relationships among species traits; (ii) habitat utilization by species; (iii) the relationship between species traits and habitat utilization; (iv) trends in species traits in a framework of spatial and temporal variability; and (v) tests of trends predicted for species traits and species richness in the framework of spatial and temporal habitat variability in terms of the river habitat templet and patch dynamics concept.2Species traits describing reproductive characteristics, food, and size had the closest relationships with each other in the various correspondence analyses performed. Faunal and floral separation by species traits produced groupings similar to those based on traditional taxonomy.3Two major gradients appear in the utilization of the floodplain habitats: a vertical gradient from interstitial to superficial habitats; and a transverse gradient from the main channel to oxbow lakes, temporary waters, and terrestrialized habitats.4For the majority of the groups examined, a statistically significant relationship was evident between the structure of the species trait and habitat utilization arrays. For these groups, the characteristics of the habitat act as a templet for species traits. Moreover, species trait modalities (i.e. categories defining traits) were significantly arranged along the axis of spatial and temporal variability for most groups, which indicates that such variability acts as a templet for species traits.5Species traits did not conform to predictions of the river habitat templet because the observed modality sequences did not follow the trends predicted in a framework of spatial and temporal variability. Moreover, there was no clear pattern in the distribution of species traits along an axis of temporal variability for groups of organisms having different sizes, which is a correlate of longevity, nor did modalities of species traits that occur under conditions of low temporal variability also tend to occur under conditions of high spatial variability (or vice versa). Clearly, species traits occur as alternative suites of characteristics in various groups of organisms.6The patch dynamics concept, which predicts that highest species richness occurs at intermediate levels of temporal variability and highest levels of spatial variability, was supported by observations in only two of the thirteen groups exaniined, and only partially (for spatial variability) when all 548 taxa were examined together.7The predictions of the river habitat templet and patch dynamics concepts were not supported, perhaps because templet theories do not yet accommodate alternative suites of characteristics and trade-offs between combinations of traits, or perhaps because the single scale of variability considered in the analyses, the inhomogeneity of the available biological information, and the aggregation of spedes traits that were used created methodological problems.8Ecologically sound river management polides eventually may be based on two key points that emerged from this synthesis: that the habitat acts as a templet for spedes traits, and that composite taxonomic groupings represent relatively homogeneous assemblages of spedes trait modalities.9The use of statistical approaches developed in this project to analyse other long-term data sets may clarify questions about the applicability of habitat templet theories to river ecology, and hasten development of ecologically sound river management policies.
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Freshwater biology 50 (2005), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Multiple biological invertebrate traits (e.g. body size, body form, dispersal potential) each described through multiple categories (e.g. small, intermediate or large body size) could serve as indicators of particular types of human impacts on large rivers. The trait composition of natural invertebrate communities is scarcely constrained by taxonomic differences among them, i.e. individual trait categories could be used to discriminate various types of human impacts across large geographic areas, which would require the definition of trait patterns for conditions of relatively low human impact.2. Using large databases to link 14 biological traits (described through 66 categories) of invertebrate genera to their occurrence in running water reaches with known environmental conditions, we examined the accuracy of various approaches to predict expected trait variation across least impacted river reaches (LIRRs) of Europe in a stepwise analytical procedure. This procedure included Monte Carlo simulations and ultimately the assignment of test-LIRRs (reaches not used in previous analyses) to the previously defined LIRR conditions.3. Distance from the source was an integrative variable capturing some (but not all) landscape features (e.g. altitude) or habitat variables (e.g. reach shear stress). Correspondingly, the relative abundance of many trait categories changed along 13 European running waters, although particularly the intensity of these changes differed among these 13 running waters.4. ‘Downstream models’ (using only distance from the source as predictor) provided the least accurate predictions of expected invertebrate trait patterns when compared with ‘landscape models’ (using distance from the source in combination with altitude and/or latitude) or ‘habitat models’ (using reach shear stress, mean annual air temperature and/or pH of the water). Landscape models provided more accurate predictions than habitat models, but the improvement of predictions of expected invertebrate traits patterns obtained using landscape models was negligible in comparison with a simpler ‘mean-model’ approach, suggesting that defining LIRR conditions through simple descriptions of frequency distributions would be sufficient for the future biomonitoring of large European rivers.5. To define these LIRR conditions, we used the average of the relative abundance of each trait category from 68 LIRRs (≥40 m wide) as expected LIRR values, and computed LIRR frequency distributions that described the deviations of the 68 individual LIRRs from these expected values. Computing such deviations from the expected LIRR values for 57 test-LIRRs (also ≥40 m wide), 57 trait categories correctly assigned 〉90% of the test-LIRRs to LIRR conditions if the latter were defined through the entire range of the LIRR frequency distributions. To the 90%-range enveloped by the LIRR frequency distributions, 42 trait categories correctly assigned 〉80% and 12 categories 〉90% of the test-LIRRs.6. Using a framework that required no regionalisation of a large geographic area, no modelling of expected values using environmental information and no standardised invertebrate sampling, the performance of our trait approach to assign test-LIRRs to LIRR conditions encourages future assessments of deviations from these defined LIRR conditions in large European river reaches with different types of human impacts.
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 42 (1999), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Current budgets for environmental management are high, tend to increase, and are used to support policy and legislation which is standardized for large geographic units. Therefore, the search for tools to monitor the effects of this investment is a major issue in applied ecology. Ideally, such a biomonitoring tool should: (1) be as general as possible with respect to its geographic application; (2) be as specific as possible by separating different types of human impact on a given ecosystem; (3) reliably indicate changes in human impact of a particular type; and (4) be derived from a sound theoretical concept in ecology.2. We developed an approach to biomonitoring which matches these ‘ideal’ characteristics by focusing on numerous, general biological species traits (e.g. size, number of descendants per reproductive cycle, parental care, mobility) and on the habitat templet concept, which relates trends in these general species traits to disturbance patterns. Using the French Rhône River and benthic macroinvertebrates as an example, we have used the data to demonstrate a general framework and the potential of our approach rather than to produce a ready-made tool. Our data covered a large river and its major tributaries, which has a catchment that crosses ecoregions, and known gradients and discontinuities in human impact.3. We applied multivariate analyses to evaluate how the distribution of species traits in invertebrate communities could discriminate environmental differences along the Rhône in comparison to traditionally used approaches (e.g. community structure, based on species abundances, or ecological species traits, such as velocity preferences and pollution tolerance). Invertebrate community structure expressed in terms either of the abundance or the traits of species reliably indicated differences in overall human impact. The community structure based on biological traits was less confounded by natural spatial gradients and reliably indicated human impact, while community structure based on ecological traits was the most confounded by natural spatial gradients and was the poorest indicator of human impact. Community structure based on species abundances was an intermediate indicator of human impact.4. These results indicate that a revision of biomonitoring approaches which have been based on a single aspect of the biological responses may be warranted. The biological traits of species could separate the different types of human impact. Therefore, the use of these traits in biomonitoring could improve existing multi-metric approaches. Future research has to show if the general applicability of species traits allows the development of a unique biomonitoring tool for running waters of the European Union, for running waters in temperate climates on several continents, for freshwater, marine and terrestrial systems, and/or for global biodiversity assessment.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 24 (1990), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. 1. Microhabitat preferences of predatory stoneflies and four prey taxa were assessed by taking benthic samples along a hydraulic gradient in a Black Forest stream in West Germany. Densities of predator and prey species were estimated at twenty-one hydraulic regimes.2. Enclosures containing the stonefly, Dinocras cephalotes, and control cages with no predators were placed in the substrate at hydraulic regimes favourable and unfavourable to predators. Cages received initial prey communities that were obtained from benthic samples taken at hydraulic regimes matching those intended for each cage.3. Population densities of the two most numerically important prey taxa, the mayfly. Baetis rhodani, and the Chironomidae, were reduced in the presence of Dinocras, but only when enclosures were placed in the hydraulic regimes favourable to the predator. Thus, predation effects increased as the hydraulic regime became more benign to the predators.4. Densities of two other prey species rare in the diets of Dinocras (Hydropsyche instabilis and Gammarus fossarum) were generally unaffected by predators regardless of the hydraulic regime.5. These data provide support for the hypothesis that perception of the abiotic regime as harsh or benign to predators is a good predictor of predator impact on densities of preferred prey species. In harsher abiotic regimes, impact will be low, while impact will be high in benign abiotic regimes.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 21 (1989), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. 1. Standard hemispheres of identical size and surface but different densities were exposed on a horizontal plane at the bottom of streams. The heaviest hemisphere moved was used as an indicator of flow conditions close to the substrate.2. Techniques of manufacture, maintenance, and use of the equipment were considered in detail.3. The method was an easily applicable and integrated indicator of key hydraulic characteristics (turbulence or force of flow prevailing at the stream bottom) previously measured in lotic benthos research, and can replace these more laborious techniques.4. The hemispheres enabled a rapid flow characterization in stream reaches, in smaller areas where the benthos was being quantitatively sampled, and in en/exclosure cages used in experimental studies.5. The method also has the potential to characterize and compare physics of flow in individual running water segments with regard to frequencies and intensities of disturbances caused by long-term variations in discharge.6. The hemispheres could be used as a standard in benthic research. since they offer a well defined scale that is directly comparable not only between studies in running waters but also in wave-exposed shores of lakes and oceans.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 17 (1987), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. 1. Based on in situ gutter trials we related the drift of caddis flies to their benthic densities and to various abiotic factors in streams in the Ivory Coast (West Africa). Members of the families Hydropsychidae, Philopotamidae. Hydroptilidae and Leptoceridae were considered in detail.2. The drift of larvae peaked at night in both early and late larval instars.3. Drift of a larval group (a certain instar, species or higher taxon) was more often related to the benthic density of other larval groups than to its own benthic density.4. Self-regulation of an upper benthic density of a larval group by emigration through drift was not statistically evident.5. There was no straightforward relationship between drift and abiotic factors.6. Drift rates differed between taxa as well as between larval instars (size groups) within a taxon. Newly hatched larvae had very high drift rates, whereas the last larval instar usually had the lowest drift rate.7. We related these results to the violently fluctuating discharge of the streams in the study area and the consequent variability of space for lotic insects.8. Drift estimates, made at the same time as a monitoring programme on possible side-effects of insecticides (Onchocerciasis Control Programme), failed to reflect benthic densities except in the night drift of Hydropsychidae.
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Freshwater biology 48 (2003), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. The application of environmental policy and legislation across large-scale administrative units creates a growing need for standard tools to assess and monitor the ‘ecological health’ of rivers, a requirement that can be achieved through the description of ecological functions of lotic invertebrate species in river communities.2. To assess alternative metrics, we tested how the functional structure (described by 14 biological traits) of invertebrate communities in 190 large river reaches differed with respect to differences in taxonomic resolution (species, genus, family), taxa weighting of traits (raw abundance, ln-transformed abundance, presence–absence data) and consideration of alien species (inclusion or exclusion), and how these differences influenced the potential of functional descriptions to discriminate river reaches across a gradient of multiple human impacts.3. Functional descriptions derived at the level of species, genera and families were very similar, whereas functional descriptions derived from raw abundances differed significantly from those derived from both ln-transformed abundances and presence–absence data. Functional descriptions after the exclusion of alien species differed considerably from those including alien species.4. Generally, the functional descriptions significantly discriminated river reaches according to the level of human impact. Taxonomic resolution scarcely influenced the discrimination of impact levels, whereas the use of raw abundances decreased impact discrimination in comparison with ln-transformed abundances and presence–absence data. Exclusion of alien species also decreased discrimination of impact levels.5. When considered separately, individual biological traits describing maximal size, number of descendants per reproductive cycle, number of reproductive cycles per individual, life duration of adults, reproductive method, parental care, body form and feeding habits had the highest potential to discriminate the level of human impact.6. Our findings indicate that genus or perhaps family identifications are sufficient for large-river biomonitoring using invertebrate traits. Although raw abundances could provide a better discrimination of low levels of human impact, presence–absence data should be sufficient to discriminate functional community changes caused by elevated levels of human impact across Europe.
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Freshwater biology 42 (1999), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. One current approach to the prediction of community characteristics is to use models of key local-scale processes (e.g. niche dimensions) affecting individuals and to estimate the effects of these attributes over larger scales. We tested this approach, focusing on how the hydraulic habitat structures fluvial fish communities.2. We used a recent statistical habitat model to predict fish community characteristics in eleven reaches in the Rhône river basin in France. Predictions were made ‘blindly’ since most reaches were not used to calibrate the model. The model reflects species preferences for local hydraulics. We made predictions of the fish community from the local hydraulic conditions found in the reaches under low flow conditions. The overall abundance and the relative abundance (both as indices) of fish species, specific size classes and species traits (i.e. reproductive, trophic, morphological and others) were predicted. We summarized our predictions of the relative abundance of species as two ‘community structure indices’ using Principal Component Analysis.3. Our predictions from low-flow hydraulics were compared with long-term observations of fish communities. The relative abundance of species actually observed depended largely on zoogeographic factors within the Rhône basin which could not be predicted by the model. The model predicted 13% of the variance in the indices of relative abundance at the species level and 23% of this variance at the trait level for all zoogeographic regions combined. However, when focused on reaches within a geographic region, the model explained up to 47% of the same variance. Therefore, geographic regions act as ‘filters’ on the relative abundance of species, but hydraulics do affect fish communities within a given geographical context.4. For the synthetic ‘community structure indices’, we obtained good predictions from hydraulics independently of the geographical context (variance explained up to 95%). These indices were linked to simple key hydraulic characteristics of river reaches (Froude and/or Reynolds number). The indices enabled interpretations of the links between hydraulics, geomorphology, discharge and community patterns. These links were consistent with existing knowledge of species and their traits.5. In addition to the above validations, the habitat model partly explained the observed effects of impoundment on fish communities.6. The present results show that stream hydraulics strongly impact fish community structure. Consequently, our findings confirm that community characteristics can be predicted using models of the local-scale habitat requirements of the species forming the community.
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Freshwater biology 43 (2000), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 〈list style="custom"〉1The methods used to indicate the biological state of streams are often based on taxonomic composition, and the abundance of species or other taxa. This ‘taxonomic structure’ varies among ecoregions and cannot be applied to wider geographical areas. Therefore, we assessed the species traits of benthic macroinvertebrates from semi-natural reference sites as a potential benchmark for large-scale biomonitoring. Our purpose was to assess the stability of community structure, based on the representation of taxa and of traits, across large gradients of geology (sedimentary to granitic), altitude (65–1982 m), geographical coordinates (0° 48′ W to 7° 20′ E and 42° 52′ to 48° 44′ N), stream order (1–5) and slope (0.5–60‰).2We used invertebrate abundance data from the 62 most natural French stream sites available. These abundance data served to weight the occurrence of ‘biological’ traits, such as reproductive characteristics, mobility, resistance forms, food, feeding habits, respiration, and ‘ecological’ traits, such as preferences for temperature, trophic level, saprobity, biogeographic distribution, longitudinal zonation, substratum and current velocity.3Multivariate analyses of taxonomic composition demonstrated a clear site gradient from lowlands to uplands and from calcareous to granitic geology. In contrast, community structure based on both biological and ecological traits was stable across environmental gradients.4The frequency distribution of biological traits indicated that the stream benthos of the ‘reference sites’ had a mixture of categories which confirmed theoretical predictions for temporally stable and spatially variable habitats. A mixture of ecological trait categories also occurred at our reference sites. Thus, semi-natural benthic macroinvertebrate communities are functionally diverse. Moreover, we included an initial application of these traits to a case of slightly to moderately polluted sites to show that the impact of humans significantly changes this natural functional diversity.5Future studies should focus on the potential for various biological and ecological traits to discriminate different human impacts on the benthic macroinvertebrates of running waters, and on the integration of this functional application into a general ‘reference-condition’ approach.
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